xlat v2: Dynamically detect need for CnP bit

ARMv8.2-TTCNP is mandatory from ARMv8.2 onwards, but it can be implemented
in CPUs that don't implement all mandatory 8.2 features (and so have to
claim to be a lower version).

This patch removes usage of the ARM_ARCH_AT_LEAST() macro and uses system
ID registers to detect whether it is needed to set the bit or not.

Change-Id: I7bcbf0c7c937590dfc2ca668cfd9267c50f7d52c
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

include/arch/aarch32/arch.h

 /*
- * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -94,12 +94,16 @@
 /* CSSELR definitions */
 #define LEVEL_SHIFT		U(1)
 
-/* ID_PFR0 AMU definitions */
+/* ID_MMFR4 definitions */
+#define ID_MMFR4_CNP_SHIFT	U(12)
+#define ID_MMFR4_CNP_LENGTH	U(4)
+#define ID_MMFR4_CNP_MASK	U(0xf)
+
+/* ID_PFR0 definitions */
 #define ID_PFR0_AMU_SHIFT	U(20)
 #define ID_PFR0_AMU_LENGTH	U(4)
 #define ID_PFR0_AMU_MASK	U(0xf)
 
-/* ID_PFR0 DIT definitions */
 #define ID_PFR0_DIT_SHIFT	U(24)
 #define ID_PFR0_DIT_LENGTH	U(4)
 #define ID_PFR0_DIT_MASK	U(0xf)
@@ -475,6 +479,7 @@
 #define DCISW		p15, 0, c7, c6, 2
 #define CTR		p15, 0, c0, c0, 1
 #define CNTFRQ		p15, 0, c14, c0, 0
+#define ID_MMFR4	p15, 0, c0, c2, 6
 #define ID_PFR0		p15, 0, c0, c1, 0
 #define ID_PFR1		p15, 0, c0, c1, 1
 #define MAIR0		p15, 0, c10, c2, 0

include/arch/aarch32/arch_features.h

+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef ARCH_FEATURES_H
+#define ARCH_FEATURES_H
+
+#include <stdbool.h>
+
+#include <arch_helpers.h>
+
+static inline bool is_armv8_2_ttcnp_present(void)
+{
+	return ((read_id_mmfr4() >> ID_MMFR4_CNP_SHIFT) &
+		ID_MMFR4_CNP_MASK) != 0U;
+}
+
+#endif /* ARCH_FEATURES_H */

include/arch/aarch32/arch_helpers.h

 /*
- * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -214,6 +214,7 @@ DEFINE_SYSREG_RW_FUNCS(cpsr)
  ******************************************************************************/
 DEFINE_COPROCR_READ_FUNC(mpidr, MPIDR)
 DEFINE_COPROCR_READ_FUNC(midr, MIDR)
+DEFINE_COPROCR_READ_FUNC(id_mmfr4, ID_MMFR4)
 DEFINE_COPROCR_READ_FUNC(id_pfr0, ID_PFR0)
 DEFINE_COPROCR_READ_FUNC(id_pfr1, ID_PFR1)
 DEFINE_COPROCR_READ_FUNC(isr, ISR)

include/arch/aarch64/arch.h

 /*
- * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -156,10 +156,6 @@
 #define ID_AA64PFR0_GIC_WIDTH	U(4)
 #define ID_AA64PFR0_GIC_MASK	((ULL(1) << ID_AA64PFR0_GIC_WIDTH) - ULL(1))
 
-/* ID_AA64MMFR0_EL1 definitions */
-#define ID_AA64MMFR0_EL1_PARANGE_SHIFT	U(0)
-#define ID_AA64MMFR0_EL1_PARANGE_MASK	ULL(0xf)
-
 /* ID_AA64ISAR1_EL1 definitions */
 #define ID_AA64ISAR1_GPI_SHIFT	U(28)
 #define ID_AA64ISAR1_GPI_WIDTH	U(4)
@@ -179,6 +175,10 @@
 #define ID_AA64ISAR1_APA_MASK \
 	(((ULL(1) << ID_AA64ISAR1_APA_WIDTH) - ULL(1)) << ID_AA64ISAR1_APA_SHIFT)
 
+/* ID_AA64MMFR0_EL1 definitions */
+#define ID_AA64MMFR0_EL1_PARANGE_SHIFT	U(0)
+#define ID_AA64MMFR0_EL1_PARANGE_MASK	ULL(0xf)
+
 #define PARANGE_0000	U(32)
 #define PARANGE_0001	U(36)
 #define PARANGE_0010	U(40)
@@ -202,6 +202,11 @@
 #define ID_AA64MMFR0_EL1_TGRAN16_SUPPORTED	ULL(0x1)
 #define ID_AA64MMFR0_EL1_TGRAN16_NOT_SUPPORTED	ULL(0x0)
 
+/* ID_AA64MMFR2_EL1 definitions */
+#define ID_AA64MMFR2_EL1		S3_0_C0_C7_2
+#define ID_AA64MMFR2_EL1_CNP_SHIFT	U(0)
+#define ID_AA64MMFR2_EL1_CNP_MASK	ULL(0xf)
+
 /* ID_AA64PFR1_EL1 definitions */
 #define ID_AA64PFR1_EL1_SSBS_SHIFT	U(4)
 #define ID_AA64PFR1_EL1_SSBS_MASK	ULL(0xf)

include/arch/aarch64/arch_features.h

+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef ARCH_FEATURES_H
+#define ARCH_FEATURES_H
+
+#include <stdbool.h>
+
+#include <arch_helpers.h>
+
+static inline bool is_armv8_2_ttcnp_present(void)
+{
+	return ((read_id_aa64mmfr2_el1() >> ID_AA64MMFR2_EL1_CNP_SHIFT) &
+		ID_AA64MMFR2_EL1_CNP_MASK) != 0U;
+}
+
+#endif /* ARCH_FEATURES_H */

include/arch/aarch64/arch_helpers.h

 /*
- * Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -449,6 +449,9 @@ DEFINE_RENAME_SYSREG_READ_FUNC(erxaddr_el1, ERXADDR_EL1)
 DEFINE_RENAME_SYSREG_READ_FUNC(erxmisc0_el1, ERXMISC0_EL1)
 DEFINE_RENAME_SYSREG_READ_FUNC(erxmisc1_el1, ERXMISC1_EL1)
 
+/* Armv8.2 Registers */
+DEFINE_RENAME_SYSREG_READ_FUNC(id_aa64mmfr2_el1, ID_AA64MMFR2_EL1)
+
 /* Armv8.3 Pointer Authentication Registers */
 DEFINE_RENAME_SYSREG_RW_FUNCS(apgakeylo_el1, APGAKeyLo_EL1)
 

lib/xlat_tables_v2/aarch32/xlat_tables_arch.c

 /*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -10,6 +10,7 @@
 #include <platform_def.h>
 
 #include <arch.h>
+#include <arch_features.h>
 #include <arch_helpers.h>
 #include <lib/cassert.h>
 #include <lib/utils_def.h>
@@ -219,13 +220,10 @@ void setup_mmu_cfg(uint64_t *params, unsigned int flags,
 	/* Set TTBR0 bits as well */
 	ttbr0 = (uint64_t)(uintptr_t) base_table;
 
-#if ARM_ARCH_AT_LEAST(8, 2)
-	/*
-	 * Enable CnP bit so as to share page tables with all PEs. This
-	 * is mandatory for ARMv8.2 implementations.
-	 */
-	ttbr0 |= TTBR_CNP_BIT;
-#endif
+	if (is_armv8_2_ttcnp_present()) {
+		/* Enable CnP bit so as to share page tables with all PEs. */
+		ttbr0 |= TTBR_CNP_BIT;
+	}
 
 	/* Now populate MMU configuration */
 	params[MMU_CFG_MAIR] = mair;

lib/xlat_tables_v2/aarch64/xlat_tables_arch.c

 /*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,7 @@
 #include <stdint.h>
 
 #include <arch.h>
+#include <arch_features.h>
 #include <arch_helpers.h>
 #include <lib/cassert.h>
 #include <lib/utils_def.h>
@@ -266,13 +267,10 @@ void setup_mmu_cfg(uint64_t *params, unsigned int flags,
 	/* Set TTBR bits as well */
 	ttbr0 = (uint64_t) base_table;
 
-#if ARM_ARCH_AT_LEAST(8, 2)
-	/*
-	 * Enable CnP bit so as to share page tables with all PEs. This
-	 * is mandatory for ARMv8.2 implementations.
-	 */
-	ttbr0 |= TTBR_CNP_BIT;
-#endif
+	if (is_armv8_2_ttcnp_present()) {
+		/* Enable CnP bit so as to share page tables with all PEs. */
+		ttbr0 |= TTBR_CNP_BIT;
+	}
 
 	params[MMU_CFG_MAIR] = mair;
 	params[MMU_CFG_TCR] = tcr;